The 57-year-old driver made off before the robber could take any cash

The 22-year-old is in critical condition in hospital after being found with serious head injuries in east London.

Scotland Yard said officers were alerted at about 10.45 last night to an incident in Downing Road, Dagenham.

The victim, a local man, was found near the junction with Darcy Gardens and taken to a hospital in Essex.

A 22-year-old man was arrested at the scene on suspicion of assault and is in custody at an east London police station.

Detectives appealed for anyone who may have seen an altercation or anything suspicious to come forward.

Acting Detective Inspector Perry Benton, of the Homicide and Serious Crime Command, said: “It is essential that anyone who may be able to assist the investigation does come forward. They may be able to help us piece together the full circumstances of the incident which has left this man fighting for his life.”

Anyone who could help was asked to call the incident room at Barking on 020-8345 3775, or if wishing to remain anonymous Crimestoppers on 0800 555 111.